AB0272 DEEP BREATHING INCREASES HEART RATE VARIABILITY IN HEALTHY PARTICIPANTS AND IN PATIENTS WITH RHEUMATOID ARTHRITIS AND SYSTEMIC LUPUS ERYTHEMATOSUS: AN INTERVENTIONAL DOSE-RESPONSE STUDY
Authors: C. H. Liboriussen, S. S. Andersen, M. K. Jensen, S. S. Andersen, M. R. Jochumsen, S. Kristensen
Journal: Annals of the Rheumatic Diseases (2022)

Background Patients with Rheumatoid Arthritis (RA) and Systemic Lupus Erythematosus (SLE) are known to have an autonomic dysfunction, especially reduced parasympathetic activity. The dysfunction can be measured through heart rate variability (HRV), an indicator of vagus nerve tone. Studies have found a potential anti-inflammatory effect of the vagus nerve and proposed vagus nerve stimulation (VNS) as an anti-inflammatory treatment. A way of stimulating the vagus nerve non-invasively could be through deep breathing (DB). Objectives The aims of this study were to examine the dose-response of DB on HRV in healthy participants and to examine the reliability of the effect of DB on HRV in patients with RA and SLE across two days. Methods The study was designed as an interventional study, more specifically the healthy subjects participated in a dose-response study and the patients with RA and SLE participated in a study of reliability. Forty-one healthy participants performed DB for 5, 15, and 30 minutes (4 seconds of inspiration and 6 seconds of expiration) in a randomized order on three different days. Fifty-two patients with RA and SLE performed the optimal dose of DB found in healthy participants, and the intervention was repeated on two different days to examine the reliability of the effect. The outcome measure was HRV, which was derived from a 5-minute electrocardiogram recording measured twice before and three times after DB. The extracted HRV measures included in the further analysis were the time domain parameters: a) The standard deviation of the R-R intervals (SDNN), b) the root mean square of successive R-R intervals (RMSSD), and c) the proportion of NN50 (pairs of successive R-R intervals that differ more than 50 milliseconds) divided by the total number of R-R intervals (PNN50). Results Thirty minutes of DB increased HRV and was the optimal dose of DB in healthy participants. In patients with RA and SLE 30 minutes of DB increased all HRV-parameters similarly across two days indicating reliability, see Figure 1. The effect of DB remained for at least 30 minutes after the intervention. Figure 1. Bar chart showing the heart rate variability-parameters plotted as mean ± standard error in patients with RA and SLE. RA: Rheumatoid Arthritis. SLE: Systemic Lupus Erythematosus. SDNN: The standard deviation of the R-R intervals. RMSSD: The root mean square of successive R-R intervals. PNN50: The proportion of NN50 (pairs of successive R-R intervals that differ more than 50 milliseconds) divided by the total number of R-R intervals. Conclusion DB increases HRV in healthy participants and in patients with RA and SLE, indicating a stimulation of the vagus nerve. Future studies are needed to investigate the potential anti-inflammatory effect as well. Acknowledgements The authors thank patients and research personnel at Aalborg University Hospital, Denmark. Disclosure of Interests None declared